Desulfurization and novel sorbent for the same

ABSTRACT

The attrition resistance of sorbent compositions are enhanced by acid-treating the perlite component of the sorbent. The efficiency of making a promoter metal-containing sorbent composition is enhanced using a novel method for incorporating the promoter metal into the sorbent.

BACKGROUND OF THE INVENTION

This invention relates to a process of making a sorbent composition, asorbent composition made by such process, and a process of using asorbent composition for the removal of sulfur from a sulfur-containingfluid.

Hydrocarbon-containing fluids such as gasoline and diesel fuelstypically contain a quantity of sulfur. High levels of sulfur in suchautomotive fuels are undesirable because oxides of sulfur present inautomotive exhaust may irreversibly poison noble metal catalystsemployed in automobile catalytic converters. Emissions from suchpoisoned catalytic converters may contain high levels of non-combustedhydrocarbons, oxides of nitrogen, and/or carbon monoxide, which, whencatalyzed by sunlight, form ground level ozone, more commonly referredto as smog.

Much of the sulfur present in the final blend of most gasolinesoriginates from a gasoline blending component commonly known as“cracked-gasoline.” Thus, reduction of sulfur levels in cracked-gasolinewill inherently serve to reduce sulfur levels in most gasolines, suchas, automobile gasolines, racing gasolines, aviation gasolines, boatgasolines, and the like.

Many conventional processes exist for removing sulfur fromcracked-gasoline. However, most conventional sulfur removal processes,such as hydrodesulfurization, tend to saturate olefins and aromatics inthe cracked-gasoline and thereby reduce its octane number (both researchand motor octane number). Thus, there is a need for a process whereindesulfurization of cracked-gasoline is achieved while the octane numberis maintained.

In addition to the need for removing sulfur from cracked-gasoline, thereis also a need to reduce the sulfur content in diesel fuel. In removingsulfur from diesel fuel by hydrodesulfurization, the cetane is improvedbut there is a large cost in hydrogen consumption. Such hydrogen isconsumed by both hydrodesulfurization and aromatic hydrogenationreactions. Thus, there is a need for a process wherein desulfurizationof diesel fuel is achieved without significant consumption of hydrogenso as to provide a more economical desulfurization process.

Traditionally, sorbent compositions used in processes for removingsulfur from sulfur-containing fluids, such as cracked-gasoline anddiesel fuel, have been agglomerates utilized in fixed bed applications.Because fluidized bed reactors have advantages over fixed bed reactors,such as better heat transfer and better pressure drop, sulfur-containingfluids are sometimes processed in fluidized bed reactors. Fluidized bedreactors generally use reactants (e.g., sorbent compositions) that arein the form of relatively small particulates. The size of theseparticulates is generally in a range of from about 1 micron to about 10millimeters. However, conventional reactant particulates generally donot have sufficient attrition resistance (i.e., resistance to physicaldeterioration) for all applications. Consequently, finding a sorbentwith sufficient attrition resistance that removes sulfur from thesesulfur-containing fluids and that can be used in fluidized, transport,moving, or fixed bed reactors is desirable and would be a significantcontribution to the art and to the economy.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a novelmethod of making a sorbent composition which is suitable for removingsulfur from sulfur-containing fluids, such as cracked-gasoline anddiesel fuels, and has enhanced attrition resistance.

A further object of this invention is to provide a sorbent compositionhaving enhanced attrition resistance.

Another object of this invention is to provide a process for the removalof sulfur from sulfur-containing fluid streams which minimizessaturation of olefins and aromatics therein.

A yet further object of this invention is to provide a process for theremoval of sulfur from sulfur-containing fluid streams which minimizeshydrogen consumption.

It should be noted that the above-listed objects need not all beaccomplished by the invention claimed herein and other objects andadvantages of this invention will be apparent from the followingdescription of the preferred embodiments and appended claims.

Accordingly, in one embodiment of the present invention, a method ofmaking a sorbent composition is provided. The method comprises the stepsof: (a) contacting expanded, crushed perlite with an acid to therebyprovide an acid-treated perlite; and (b) combining the acid-treated,expanded, crushed perlite with a zinc source, an aluminum source, and apromoter metal to thereby provide an unreduced sorbent.

In a further embodiment of the present invention, there is provided asorbent composition comprising perlite, zinc oxide, and areduced-valence promoter metal component. The sorbent composition has anOperational Jet Cup Attrition Index value of less than about 16.

In another embodiment of the present invention, there is provided amethod of making a sorbent composition comprising the steps of: (a)reacting a promoter metal-containing compound with a zinc-containingcompound under conditions sufficient to form a substitutional solidsolution comprising a promoter metal and zinc; and (b) combining thesubstitutional solid solution with a zinc source and an aluminum sourceto thereby provide an unreduced sorbent.

In yet another embodiment of the present invention, there is provided amethod of making a sorbent composition comprising the steps of: (a)admixing a solvent, a promoter metal, and an alumina to thereby form awet mix; (b) admixing zinc oxide and perlite to thereby form a dry mix;(c) admixing the wet mix and the dry mix to thereby form a sorbentslurry; (d) particulating the sorbent slurry to thereby form sorbentparticulates; (e) calcining the sorbent particulates to thereby formcalcined sorbent particulates; and (f) reducing the calcined sorbentparticulates to thereby form a reduced sorbent.

In still another embodiment of the present invention, there is provideda method of making a sorbent composition comprising the steps of: (a)admixing a solvent and an alumina to thereby form a wet mix; (b)admixing zinc oxide, an oxide of a promoter metal, and perlite tothereby form a dry mix; (c) admixing the wet mix and the dry mix tothereby form a sorbent slurry; (d) particulating the sorbent slurry tothereby form sorbent particulates; (e) calcining the sorbentparticulates to thereby form calcined sorbent particulates; and (f)reducing the calcined sorbent particulates to thereby form a reducedsorbent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a desulfurization unit, particularlyillustrating the circulation of regenerable solid sorbent particulatesthrough a reactor, a regenerator, and a reducer.

FIG. 2 is a schematic diagram of a system used in determining theOperational Jet Cup Attrition Index of a sorbent composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with a first embodiment of the present invention, a novelprocess for making a sorbent composition is provided. The processgenerally comprises the steps of: (a) contacting perlite with an acid tothereby provide an acid-treated perlite; (b) combining supportcomponents including the acid-treated perlite, a zinc source, analuminum source, a solvent, and, optionally, a filler; (c) mixing thesupport components to provide a substantially homogeneous supportmixture in the form of a slurry; (d) shaping the support mixture intosupport particulates by spray drying the support mixture intomicrospherical particles; (e) calcining the support particulates tothereby provide calcined support particulates having a zinc aluminatecomponent formed from at least a portion of the zinc source and at leasta portion of the aluminum source; (f) incorporating a promoter metalwith the calcined support particulates by impregnation with an aqueoussolution containing the promoter metal, thereby providing a promotedsorbent; (g) calcining the promoted sorbent to thereby provide acalcined promoted sorbent having an oxidized promoter metal componentcomprising a substitutional solid metal oxide solution characterized bythe following formula: M_(X)Zn_(Y)O, wherein M is the promoter metal andX and Y are numerical values in the range of from 0.01 to 0.99; (h)reducing the calcined promoted sorbent to thereby provide a reducedsorbent having a reduced-valence promoter metal component comprising asubstitutional solid metal solution characterized by the followingformula: M_(A)Zn_(B), wherein M is the promoter metal and A and B arenumerical values in the range of from about 0.01 to about 0.99.

The perlite employed in step (a), described above, is preferablyexpanded perlite formed from a siliceous volcanic rock (i.e., crudeperlite) that has been heated to a temperature above about 1,600° F. tothereby cause expansion of the rock to a size that is at least fourtimes its initial size. Crude perlite rock expands (typically four to 20times its original size) at high temperatures due to the presence ofwater in the rock. When the crude perlite is heated above about 1,600°F., the water in the rock vaporizes and creates numerous tiny bubbles inthe heat-softened glassy particles. These diminutive glass-sealedbubbles are then crushed into curved pieces which account for the lowdensity of expanded perlite. Expanded perlite typically has a density inthe range of from about one to about 15 pounds per cubic foot, moretypically two to six pounds per cubic foot. An elemental analysis ofexpanded perlite typically shows the following components inapproximately the following amounts: silicon, 33.8%; aluminum, 7.2%;potassium, 3.5%; sodium, 3.4%; iron, 0.6%; calcium, 0.6%; magnesium,0.2%; oxygen (by difference), 47.5%; and bound water, 3.0%. Preferably,the perlite employed in the present invention comprises the above-listedcomponents in amounts within about 25 percent of the above-listedamounts, more preferably in amounts within 10 percent of theabove-listed amounts.

The expanded perlite is preferably subjected to crushing or milling toreduce the particle size of the perlite prior to implementation in thepresent invention. It is preferred for the perlite employed in step (a)to have a mean particle size in the range of from about five to about 75microns, more preferably in the range of from about 20 to about 50microns, and most preferably in the range of from 30 to 40 microns.Preferably, the amount of the perlite having a particle size of morethan 75 microns is less than about 30 weight percent, more preferablyless than about 15 weight percent, and most preferably less than fiveweight percent. Preferably, the amount of the perlite having a particlesize of less than 2 microns is less than about 30 weight percent, morepreferably less than about 15 weight percent, and most preferably lessthan five weight percent.

The acid contacted with the perlite in step (a), described above, can beany suitable organic or inorganic acid that can alter the perlite in amanner such that the attrition resistance of the resulting calcinedpromoted sorbent composition is enhanced. Suitable inorganic acidsinclude, for example, nitric acid, hydrochloric acid, sulfuric acid, andphosphoric acid. Suitable organic acids include, for example,chloroacetic acid, trichloroacetic acid, maleic acid, malonic acid, andoxalic acid. Preferably, the acid is an inorganic acid having aconcentration of about ten percent or less. Most preferably, the acid isnitric acid having a concentration of about five percent. The perliteand acid can be contacted with one another by any suitable means knownin the art including, for example, by dipping the perlite into the acid,by extensively washing the perlite with the acid, or by submerging theperlite in the acid. Preferably, the perlite and the acid are contactedwith one another for a time period in the range of from about 30 secondsto about 60 minutes, most preferably in the range of from about oneminute to about 20 minutes. It is preferred that the resultingacid-treated perlite substantially retains the micropores (<500angstroms) originally present and that the acid does not etch theperlite to any appreciable degree. It is further preferred that the acidtreatment does not create any appreciable amount of new macropores (>500angstroms).

Though not wishing to be bound by theory, the inventors postulate thatthe acid treatment of perlite results in a final sorbent compositionhaving enhanced attrition resistance due to the increased bindingstrength between the acid-treated perlite particles and the alumina. Itis believed that the acid treatment of the perlite significantlyincreases the number of hydroxyl groups on the surface of the particlewhich can result in a strong bind between the acid-treated perlite andalumina upon calcination.

The zinc source employed in step (b), described above, can be anyzinc-containing compound. Preferably, the zinc source is in the form ofzinc oxide or one or more zinc compounds that are convertible to zincoxide. Most preferably, the zinc source is in the form of a powderedzinc oxide. The zinc source, preferably powdered zinc oxide, willgenerally be present in the support mixture in an amount in the range offrom about 2 to about 70 weight percent based on a total weight of thesupport mixture, more preferably in the range of from about 5 to about50 weight percent, and most preferably in the range of from 10 to 45weight percent.

The aluminum source employed in step (b), described above, can be anyaluminum-containing carrier compound. The aluminum source can be anysuitable commercially available alumina material including, but notlimited to, colloidal alumina solutions, hydrated aluminas, peptizedaluminas, and, generally, those alumina compounds produced by thedehydration of alumina hydrates. The preferred alumina source is ahydrated alumina such as, for example, boehmite or pseudoboehmite. Thealuminum source, preferably a hydrated alumina, will generally bepresent in the support mixture in an amount such that the weight ratioof the zinc source to the aluminum source in the support mixture is inthe range of from about 0.1:1 to about 20:1, more preferably in therange of from about 1:1 to about 10:1, and most preferably in the rangeof from 2:1 to 6:1.

The perlite employed in step (a), described above, should be present inthe support mixture in an amount such that the weight ratio of the zincsource to the perlite is in the range of from about 0.5:1 to about 20:1,more preferably in the range of from 1:1 to about 10:1, and mostpreferably in the range of from 2:1 to 6:1.

The solvent employed in step (b), described above, can be any liquidadded to the support mixture to help form a support mixture having anoptimum consistency for shaping, preferably by spray drying. The mostpreferred solvent is distilled water. The solvent, preferably distilledwater, should be present in the support mixture in an amount such thatthe weight ratio of the zinc source to the solvent is in the range offrom about 0.05:1 to about 2:1, more preferably in the range of fromabout 0.1:1 to about 1.5:1, and most preferably in the range of from0.2:1 to 1:1. When a filler is employed in step (b), described above,the filler can be any compound which enhances the ability of the supportmixture to be spray dried. Preferably, the filler is a clay such as, forexample, kaolin clay. When the support mixture includes a filler,preferably kaolin clay, the filler should be present in the supportmixture in an amount which provides a weight ratio of the zinc source tothe filler in the range of from about 0.1:1 to about 20:1, morepreferably in the range of from about 1:1 to about 10:1, and mostpreferably in the range of from 2:1 to 6:1.

In accordance with step (c), described above, the combined supportcomponents are generally mixed by any suitable method or manner whichprovides for the intimate mixing of such components to thereby provide asubstantially homogeneous mixture of the support components. Anysuitable means for mixing the support components can be used to achievethe desired dispersion of such components. Examples of suitable mixingmeans include, but are not limited to, mixing tumblers, stationeryshells or troughs. Muller mixers, which are of the batch or continuoustype, impact mixers, and the like. It is presently preferred to use aMuller mixer in the mixing of the support components. The supportcomponents are admixed to provide a resulting support mixture which canbe in the form selected from the group consisting of a wet mix, a dough,a paste, a slurry, and the like.

In accordance with step (d), described above, the resulting supportmixture can then be shaped to form a particulate(s) selected from thegroup consisting of a granulate, an extrudate, a tablet, a sphere, apellet, a microsphere, and the like. Preferably, the support mixture isin the form of a slurry, and the shaping of the slurry into particulatesis achieved by spray drying the slurry to form microspheres having amean particle size generally in the range of from about 10 microns toabout 300 microns, preferably in the range of from about 40 microns toabout 150 microns, and most preferably in the range of from 50 to 100microns. Spray drying is known in the art and is discussed in Perry'sChemical Engineers Handbook, 6th Edition, published by McGraw-Hill, Inc.at pages 20-58. Additional information can be obtained from the Handbookof Industrial Drying, published by Marcel Dekker, Inc. at pages 243-293.

After shaping, preferably spray drying, the support particulates arepreferably dried and calcined in accordance with step (e), describedabove. Any drying method(s) known to one skilled in the art such as, forexample, air drying, heat drying, vacuum drying, and the like andcombinations thereof, can be used. Preferably, the support particulatesare dried at a temperature in the range of from about 180° F. to about400° F., more preferably in the range of from 200° F. to 350° F. Thepressure employed during drying of the support particulates can be inthe range of from about atmospheric (i.e., 14.7 pounds per square inchabsolute) to about 150 pounds per square inch absolute (psia), morepreferably in the range of from about atmospheric to about 100 psia, andmost preferably about atmospheric, so long as the desired temperaturecan be maintained. Any suitable period for drying the supportparticulates can be employed. Preferably, the drying of the supportparticulates takes place during a time period in the range of from about0.5 hour to about 60 hours, more preferably in the range of from onehour to 20 hours.

The calcining of the dried support particulates can be performed in anoxygen environment at a calcination temperature in the range of fromabout 400° F. to about 1800° F., more preferably in the range of fromabout 600° F. to about 1600° F., and most preferably in the range offrom 800° F. to 1500° F. The calcination pressure is preferably in therange of from about seven psia to about 750 psia, more preferably in therange of from about seven psia to about 450 psia, and most preferably inthe range of from seven psia to 150 psia. The time period for thecalcination of the dried support particulates is generally in the rangeof from about one hour to about 60 hours, more preferably in the rangeof from about 1.5 hours to about 20 hours, and most preferably in therange of from two hours to 15 hours.

During calcination of the support particulates, at least a portion ofthe zinc source and at least of portion of the aluminum sourcechemically combine to form a spinel structure similar to zinc aluminate(ZnAl₂O₄). The zinc aluminate may not be stoichiometrically pure. Thecalcined support particulates preferably comprise zinc aluminate in anamount in the range of from about two to about 40 weight percent basedon the total weight of the calcined support particulates, morepreferably in the range of from about five to about 30 weight percent,and most preferably in the range of from 10 to 20 weight percent.

In accordance with step (f), described above, the resulting calcinedsupport particulates can then be contacted with a promoter metal sourceto thereby incorporate the promoter metal with the calcined supportparticulates. The promoter metal can be at least one metal selected fromthe group consisting of nickel, cobalt, iron, manganese, tungsten,silver, gold, copper, platinum, zinc, tin, ruthenium, molybdenum,antimony, vanadium, iridium, chromium, palladium, and rhodium.Preferably, the promoter metal is selected from the gouop consisting ofnickel, cobalt and mixtures thereof; most preferably, for best sulfurremoval, the promoter metal is nickel. The promoter metal may beincorporated on, in, or with the calcined support particulates by anysuitable means or method known in the art such as, for example,impregnating, soaking, spraying, and combinations thereof. The preferredmethod of incorporating the promoter metal with the calcined supportparticulates is impregnating using standard incipient wetnessimpregnation techniques. A preferred impregnation method employs animpregnation solution comprising the desired concentration of thepromoter metal so as to ultimately provide a promoted sorbent comprisingthe desired quantity of the promoter metal. The impregnation solutioncan be an aqueous solution formed by dissolving the promoter metalsource in a solvent, preferably water. It is acceptable to use somewhatof an acidic solution to aid in the dissolution of the promoter metalsource. It is most preferred for the calcined support particulates to beimpregnated with the promoter metal by using a solution containingnickel nitrate hexahydrate dissolved in water.

Generally, the amount of the promoter metal incorporated, preferablyimpregnated, onto, into or with the calcined support particulates, is anamount which provides, after the promoted sorbent particulate materialhas been dried and calcined, a promoted sorbent composition comprisingthe promoter metal in an amount in the range of from about one to about60 weight percent promoter metal based on the total weight of thepromoted sorbent, more preferably an amount in the range of from aboutfive to about 50 weight percent promoter metal, and most preferably inan amount in the range of from 10 to 40 weight percent promoter metal.It may be necessary to employ one or more incorporation steps in orderto incorporate the desired quantity of the promoter metal with thecalcined support particulates. If so, such additional incorporation(s)are performed in substantially the same manner as described above.

Once the promoter metal has been incorporated on, in, or with thecalcined support particulates, the promoted sorbent particulates arethen dried and calcined in accordance with step (g), described above.The drying and calcining of the promoted sorbent particulates can beaccomplished by any suitable method(s) known in the art. Preferably, thedrying and calcining of the promoted sorbent particulates is performedin substantially the same manner and under substantially the sameconditions as previously described in step (e) with reference to thedrying and calcining of the unpromoted support particulates.

When the promoted sorbent particulates are calcined, at least a portionof the promoter metal and at least a portion of the zinc oxide presentin the promoted sorbent chemically combine to form an oxidized promotermetal component. Preferably, the oxidized promoter metal componentcomprises, consists essentially of, or consists of a substitutionalsolid metal oxide solution characterized by the formula: M_(X)Zn_(Y)O,wherein M is the promoter metal and X and Y are each numerical values inthe range of from about 0.01 to about 0.99. In the above formula, it ispreferred for X to be in the range of from about 0.5 to about 0.9 andmost preferably from 0.6 to 0.8. It is further preferred for Y to be inthe range of from about 0.1 to about 0.5, and most preferably from 0.2to 0.4. Preferably, Y is equal to (1−X).

Substitutional solid solutions have unique physical and chemicalproperties that are important to the chemistry of the sorbentcomposition described herein. Substitutional solid solutions are asubset of alloys that are formed by the direct substitution of thesolute metal for the solvent metal atoms in the crystal structure. Forexample, it is believed that the substitutional solid metal oxidesolution (M_(X)Zn_(Y)O) found in the oxidized (i.e., unreduced),calcined sorbent composition made by the process of the presentinvention is formed by the solute zinc metal atoms substituting for thesolvent promoter metal atoms. There are three basic criteria that favorthe formation of substitutional solid solutions: (1) the atomic radii ofthe two elements are within 15 percent of each other; (2) the crystalstructures of the two pure phases are the same; and (3) theelectronegativities of the two components are similar. The promotermetal (as the elemental metal or metal oxide) and zinc oxide employed inthe inventive sorbent composition preferably meet at least two of thethree criteria set forth above. For example, when the promoter metal isnickel, the first and third criteria, are met, but the second is not.The nickel and zinc metal atomic radii are within 10 percent of eachother and the electronegativities are similar. However, nickel oxide(NiO) preferentially forms a cubic crystal structure, while zinc oxide(ZnO) prefers a hexagonal crystal structure. A nickel zinc oxide solidsolution retains the cubic structure of the nickel oxide. Forcing thezinc oxide to reside in the cubic structure increases the energy of thephase, which limits the amount of zinc that can be dissolved in thenickel oxide structure. This stoichiometry control manifests itselfmicroscopically in a 70:30 nickel zinc oxide solid solution(Nio_(0.7)Zn_(0.3)O) that is formed during oxidation (i.e., calcinationor regeneration) and microscopically in the repeated regenerability ofthe sorbent.

During calcination of the promoted sorbent particulates, at least aportion of the promoter metal combines with at least a portion of thezinc aluminate to form a promoter metal-zinc aluminate substitutionalsolid solution characterized by the formula: M_(Z)Zn_((1-Z))Al₂O₄),wherein Z is a numerical value in the range of from 0.01 to 0.99.

The calcined promoted sorbent particulates preferably comprise zincoxide, the oxidized promoter metal component (M_(X)Zn_(Y)O), theacid-treated, expanded, crushed perlite, and the promoter metal-zincaluminate (M_(Z)Zn_((1-Z))Al₂O₄) in the ranges provided below inTable 1. TABLE 1 Components of the Calcined Promoted SorbentParticulates Range ZnO M_(X)Zn_(Y)O Perlite M_(Z)Zn_((1-Z))Al₂O₄ (wt %)(wt %) (wt %) (wt %) Preferred  5-80  5-70  5-50 1-50 More Preferred20-60 15-60 10-40 5-30 Most Preferred 30-50 20-40 15-30 10-20 

In accordance with step (h), described above, the calcined promotedsorbent particulates are thereafter subjected to reduction with asuitable reducing agent, preferably hydrogen, under reducing conditions,to thereby provide a reduced sorbent composition. Reduction can becarried out at a temperature in the range of from about 100° F. to about1500° F. and a pressure in the range of from about 15 psia to about 1500psia. Such reduction can be carried out for a time period sufficient toachieve the desired level of reduction, generally a time period in therange of from about 0.1 hour to about 20 hours.

During reduction of the calcined promoted sorbent particulates, at leasta portion of the oxidized promoter metal component is reduced to providea reduced-valence promoter metal component. Preferably, thereduced-valence promoter metal component comprises, consists essentiallyof, or consists of a substitutional solid metal solution characterizedby the formula: M_(A)Zn_(B), wherein M is the promoter metal and A and Bare numerical values in the range of from about 0.01 to about 0.99. Inthe above formula for the substitutional solid metal solution, it ispreferred for A to be in the range of from about 0.70 to about 0.97,more preferably in the range of from about 0.80 to about 0.95, and mostpreferably in the range of from about 0.90 to about 0.94. It is furtherpreferred for B to be in the range of from about 0.03 to about 0.30,more preferably in the range of from about 0.05 to about 0.20, and mostpreferably in the range of from about 0.06 to 0.10. Preferably, B isequal to (1−A). As used herein, the term “reduced-valence promoter metalcomponent” shall denote a promoter metal-containing component thatinitially had one or more oxygen atoms associated with it, but now has areduced number of oxygen atoms associated with it due to reduction.Preferably, a substantial portion of the reduced-valence promoter metalcomponent has no oxygen atoms associated with it.

The reduced sorbent particulates preferably comprise zinc oxide, thereduced-valence promoter metal component (M_(A)Zn_(B)), the acid-treatedperlite, and the promoter metal-zinc aluminate substitutional solid(M_(Z)Zn_((1-Z))Al₂O₄) in the ranges provided below in Table 2. TABLE 2Components of the Reduced Sorbent Particulates Range ZnO M_(A)Zn_(B)Perlite M_(Z)Zn_((1-Z))Al₂O₄ (wt %) (wt %) (wt %) (wt %) Preferred  5-80 5-80  5-50 1-50 More Preferred 20-60 20-60 10-40 5-30 Most Preferred30-50 30-40 20-30 10-20 

The physical properties of the reduced sorbent particulatessignificantly affect its suitability for use in the desulfurizationprocess, described in detail below. Important physical properties of thereduced sorbent particulates include, for example, particle shape,particle size, particle density, and resistance to attrition.

The reduced sorbent particulates preferably have high resistance toattrition. As used herein, the term “attrition resistance” denotes ameasure of a particle's resistance to size reduction under controlledconditions of turbulent motion. The attrition resistance of a particlecan be quantified using the jet cup attrition test, similar to theDavison Index. The Jet Cup Attrition Index represents the weight percentof the over 44 micrometer (μ) particle size fraction which is reduced toparticle sizes of less than 37 micrometers under test conditions andinvolves screening a 5 gram sample of sorbent to remove particles in the0 to 44 micrometer size range. The particles above 44 micrometers arethen subjected to a tangential jet of air at a rate of 21 liters perminute introduced through a 0.0625 inch orifice fixed at the bottom of aspecially designed jet cup (1″ I.D.×2″ height) for a period of 1 hour.The jet cup attrition test is calculated as follows:

The Correction Factor (presently 0.3) is determined by using a knowncalibration standard to adjust for differences in jet cup dimensions andwear. The solid sorbent particulates employed in the present inventionpreferably have a jet cup attrition index value of less than of lessthan about 20, more preferably less than about 15, still more preferablyless than about 12, and most preferably less than 10.

An important aspect of the present invention is that the Jet CupAttrition Index value of the inventive sorbent prepared withacid-treated perlite remains in the desired range, even after beingemployed to remove sulfur from a hydrocarbon fluid. Many conventionalsorbents have a tendency to “soften” after reaction and/or regeneration,but the inventive sorbent substantially maintains its hardness andattrition resistance over multiple cycles of desulfurization,regeneration, and reduction. One way to quantify such resistance tosoftening during operation is known as an “Operational Jet Cup AttritionIndex.” The Operational Jet Cup Attrition Index of a sorbent is simplythe Jet Cup Attrition Index of the sorbent, measured after a certainrepeated reduction/oxidation (redox) procedure) described in detailbelow. The repeated redox procedure is designed to simulate theconditions which the sorbent would be exposed to in an actualdesulfurization unit, such as desulfurization unit 10 illustrated inFIG. 1.

Referring to FIG. 2, a redox test system 100 generally includes ahydrogen source 102, an air source 104, a nitrogen source 106, and areactor tube 108. Three mass flow controllers 110, 112, 114 control theflow rate of hydrogen, air, and nitrogen, respectively, through reactortube 108. The hydrogen and air pass through a manual three-way valve116, which prevents both hydrogen and air from flowing to reactor tube108 at the same time. Reactor tube 108 is a 26-inch quartz reactor tubecontaining a three-inch upper section with a 0.5-inch outer diameter(O.D.), a 20-inch reactor section (one-inch O.D.) with a glass frit 117centered in the reactor section, and a three-inch lower section(0.5-inch O.D.). Reactor tube 108 is positioned in a 15-inch long clamshell furnace 118. A thermocouple 120 is disposed at the upper end ofreactor tube 108 and extends down into reactor tube 108, three inchesabove the glass frit 117. Thermocouple 120 is connected to a temperaturereadout and is not temperature controlling. Two temperature controllingthermocouples 122, 124 are connected through the side of two-zone clamshell furnace 118. A side port 126 at the top of reactor tube 108 isfluidly coupled to a vent line 128. An inlet port 130 of reactor tube108 is fluidly coupled to hydrogen, air, and nitrogen sources 102, 104,106 via a supply line 132.

To perform the repeated redox procedure in redox test system 100, thesorbent particulates are first screened to remove particles smaller than325 mesh and larger than 100 mesh. A ten gram quantity of the screensorbent particulates is then loaded on the top of the glass frit 117through the top of reactor tube 108. Nitrogen is then turned on at 200standard cubic centimeters per minute (SCCM) and reactor tube 108 ispurged with nitrogen for 15 minutes. Reactor tube 108 is then heated to800° F. in flowing nitrogen for 15 minutes. The nitrogen flow is thenstopped and the hydrogen flow rate is set to 300 SCCM. The sorbent isallowed to reduce in flowing hydrogen for one hour. The hydrogen flow isthen stopped, and nitrogen is set to flow at 200 SCCM for 15 minuteswhile reactor tube 108 is heated to 950° F. The nitrogen flow is thenstopped and air is turned on to 100 SCCM and the sorbent is allowed tooxidize for one hour. The air is then shut off and nitrogen is allowedto purge reactor tube 108 for 15 minutes at 200 SCCM. The above purge,reduction, purge, oxidation, and purge steps are then repeated two moretimes for a total of three redox cycles. After the three redox cycles,the nitrogen is stopped and the hydrogen flow rate is set to 300 SCCMand the sorbent is allowed to reduce for one hour. The hydrogen flow isthen stopped and nitrogen set to a flow at 200 SCCM for 15 minutes. Thenitrogen flow is then stopped and reactor tube 108 is allowed to cool toambient temperature. The sorbent, having been subjected to 3.5 redoxcycles, is then removed from reactor tube 108 and the Jet Cup AttritionIndex of this sorbent is determined in the manner described above. Theresulting Jet Cup Attrition Index of the “aged” sorbent subjected to 3.5redox cycles is the “Operational Jet Cup Attrition Index.”

It has been discovered that a sorbent employing acid-treated perlite hasa lower Operational Jet Cup Attrition Index (improved attritionresistance) than a sorbent employing untreated perlite. It is preferredfor the inventive reduced sorbent particulates (comprising acid-treatedperlite) to have an Operational Jet Cup Attrition Index value of lessthan about 20, more preferably less than about 15, still more preferablyless than about 13, and most preferably less than 12.

It has also been discovered that the difference between the Jet CupAttrition Index of a freshly prepared sorbent and the Operational JetCup Attrition Index of the aged sorbent is much less for sorbentsemploying acid-treated perlite than for sorbents employing untreatedperlite. Such a minimal reduction in Jet Cup Attrition Index duringoperation indicates that the sorbent employing acid-treated perlite doesnot soften as much as the untreated sorbent during use. Preferably, theOperational Jet Cup Attrition Index value of the inventive sorbent(employing acid-treated perlite) is within 50 percent of the Jet CupAttrition Index value for that sorbent in its freshly prepared state(i.e., the “Fresh” Jet Cup Attrition Index), more preferably OperationalJet Cup Attrition Index value and “Fresh” Jet Cup Attrition Index valueare within about 30 percent of each other, more preferably within about20 percent, still more preferably within about 10 percent, and mostpreferably within 7.5 percent.

The reduced sorbent particulates preferably comprise substantiallymicrospherical particles having a mean particle size in the range offrom about 10 to about 300 microns, more preferably in the range of fromabout 40 to 150 microns, and most preferably in the range of from 50 to100 microns. The density of the sorbent particulates is preferably inthe range of from about 0.5 to about 1.5 grams per cubic centimeter(g/cc), more preferably in the range of from about 0.8 to about 1.3g/cc, and most preferably in the range of from 0.9 to 1.2 g/cc. Theparticle size and density of the sorbent particulates preferably qualifythe sorbent particulates as a Group A solid under the Geldart groupclassification system described in Powder Technol., 7, 285-292 (1973).

In accordance with a second embodiment of the present invention, a novelprocess for making a sorbent composition is provided. The processgenerally comprises the steps of: (aa) reacting a promotermetal-containing compound with a zinc-containing compound underconditions sufficient to form a substitutional solid solution comprisingthe promoter metal and zinc; (bb) combining support components includingthe substitutional solid solution, a zinc source, an aluminum source,perlite, a solvent, and, optionally, a filler; (cc) mixing the supportcomponents to provide a substantially homogenous support mixture in theform of a slurry; (dd) shaping the support mixture into supportparticulates by spray drying the support mixture into microsphericalparticles; (ee) calcining the support particulates to thereby provide acalcined promoted sorbent having an oxidized promoter metal componentcomprising a substitutional solid metal oxide solution characterized bythe following formula: M_(X)Zn_(Y)O, wherein M is the promoter metal andX and Y are numerical values in the range of from 0.01 to 0.99; and (ff)reducing the calcined promoted sorbent to thereby provide a reducedsorbent having a reduced-valence promoter metal component comprising asubstitutional solid metal solution characterized by the followingformula: M_(A)Zn_(B), wherein M is the promoter metal and A and B arenumerical values in the range of from about 0.01 to about 0.99.

The promoter metal-containing compound employed in step (aa), describedabove, can be any compound comprising the promoter metal (describedabove in the first embodiment of the present invention) and capable ofbeing reacted with the zinc-containing compound to form a substitutionalsolid solution comprising the promoter metal and zinc. Preferably, boththe promoter metal-containing compound and the zinc-containing compoundare acetates. Most preferably, the promoter metal-containing compound isnickel acetate tetrahydrate and the zinc-containing compound is zincacetate dihydrate. The amounts of the promoter metal-containing compoundand zinc-containing compound employed in step (aa) are preferably suchthat the molar ratio of nickel to zinc is in the range of from about0.5:1 to about 10:1, more preferably in the range of from about 1:1 toabout 4:1, and most preferably in the range of from about 2:1 to about3:1. The promoter metal-containing compound and zinc-containing compoundcan be reacted with one another using any suitable method known in theart for producing a substitutional solid solution comprising thepromoter metal and zinc. Preferably, the promoter metal-containingcompound and zinc-containing compound are reacted with one another byfirst mixing the two compounds under heated conditions, and thereaftercalcining the mixture under calcining conditions, described above.

The substitutional solid solution formed by the reaction of the promotermetal-containing compound and the zinc-containing compound is preferablya substitutional solid metal oxide solution characterized by theformula: M_(X)Zn_(Y)O, wherein M is the promoter metal and X and Y arenumerical values in the range of from 0.01 to 0.99. In the aboveformula, it is preferred for X to be in the range of from about 0.5 toabout 0.9, more preferably from 0.6 to 0.8, and most preferably about0.7. It is further preferred for Y to be in the range of from about 0.1to about 0.5, more preferably from 0.2 to 0.4, and most preferably about0.3. Preferably, Y is equal to (1−X).

The zinc source, aluminum source, perlite, solvent, and filler employedin step (bb), described above, can be the same compounds described instep (b) of the first embodiment of the present invention. Steps(bb)-(ff) can be performed in any manner known in the art that providesa resulting reduced sorbent having components and propertiessubstantially similar to those of the reduced sorbent described above inthe first embodiment of the present invention. Preferably, steps(bb)-(ff) are carried out in a manner similar to that disclosed in thefirst embodiment of the present invention.

In accordance with a third embodiment of the present invention, a novelprocess for making a sorbent composition is provided. The processgenerally comprises the steps of: (aaa) admixing an aluminum source, asolvent, and a soluble promoter metal to thereby form a wet mix; (bbb)admixing a zinc source, perlite, and optionally, a filler to therebyform a dry mix; (ccc) admixing the wet mix and the dry mix to therebyform a sorbent slurry; (ddd) shaping the sorbent slurry into sorbentparticulates by spray drying the sorbent slurry into microsphericalparticles; (eee) calcining the sorbent particulates to thereby formcalcined sorbent particulates having an oxidized promoter metalcomponent comprising a substitutional solid metal oxide solutioncharacterized by the following formula: M_(X)Zn_(Y)O, wherein M is thepromoter metal and X and Y are numerical values in the range of from0.01 to 0.99; and (fff) reducing the calcined sorbent particulates tothereby form a reduced sorbent having a reduced-valence promoter metalcomponent comprising a substitutional solid solution characterized bythe following formula: M_(A)Zn_(B), wherein M is the promoter metal andA and B are numerical values in the range of from about 0.01 to about0.99.

The zinc source, aluminum source, solvent, perlite, and filler employedin steps (aaa) and (bbb), described above, can be the same compoundsdescribed in the first embodiment of the present invention. The solublepromoter metal employed in step (aaa), described above, can be anycompound containing the promoter metal (preferably nickel) that can bedissolved in the wet mix. Preferably, the soluble promoter metal is anitrate. Most preferably, the soluble promoter metal is nickel nitrate.It is preferred for the pH of the wet mix and the sorbent slurry to bemaintained below five at all times.

The proportional amounts of the zinc source, aluminum source, perlite,solvent, and, optionally, filler employed in steps (aaa) and (bbb),described above, are preferably amounts which yield a sorbent slurry instep (ccc) having a ratio of such components that is substantially thesame as the support mixture described in step (c) of the firstembodiment of the present invention. The particulating, calcining, andreducing of steps (ddd), (eee), and (fff) can be performed insubstantially the same manner described above in the first embodiment ofthe present invention. The composition of the reduced sorbent producedin step (fff) is preferably substantially the same as the composition ofthe reduced sorbent provided in step (h) of the first embodiment of thepresent invention.

In accordance with a fourth embodiment of the present invention, a novelprocess for making a sorbent composition is provided. The processgenerally comprises the steps of: (aaaa) admixing a solvent and analuminum source to thereby form a wet mix; (bbbb) admixing a zincsource, an oxide of a promoter metal, perlite, and, optionally, a fillerto thereby form a dry mix; (cccc) admixing the wet mix and the dry mixto thereby form a sorbent slurry; (dddd) shaping the sorbent slurry intosorbent particulates by spray drying the sorbent slurry intomicrospherical particles; (eeee) calcining the sorbent particulates tothereby form calcined sorbent particulates having an oxidized promotermetal component comprising a substitutional solid metal oxide solutioncharacterized by the following formula: M_(X)Zn_(Y)O, wherein M is thepromoter metal and X and Y are numerical values in the range of from0.01 to 0.99; and (ffff) reducing the calcined sorbent particulates tothereby form a reduced sorbent having a reduced-valence promoter metalcomponent comprising a substitutional solid solution characterized bythe following formula: M_(A)Zn_(B), wherein M is the promoter metal andA and B are numerical values in the range of from about 0.01 to about0.99.

The zinc source, aluminum source, solvent, perlite, and filler employedin steps (aaaa) and (bbbb), described above, can be the same compoundsdescribed in the first embodiment of the present invention. It ispreferred for the pH of the wet mix and the sorbent slurry to bemaintained below six at all times.

The proportional amounts of the zinc source, aluminum source, perlite,solvent, and, optionally, filler employed in steps (aaaa) and (bbbb),described above, are preferably amounts which yield a sorbent slurry instep (cccc) having a ratio of such components that is substantially thesame as the support mixture described in step (c) of the firstembodiment of the present invention. The particulating, calcining, andreducing of steps (dddd), (eeee), and (ffff) can be performed insubstantially the same manner described above in the first embodiment ofthe present invention. The composition of the reduced sorbent producedin step (ffff) is preferably substantially the same as the compositionof the reduced sorbent provided in step (h) of the first embodiment ofthe present invention.

It should be noted that various combinations of the sorbent preparationprocedures described in the first, second, third, and fourth embodimentsof the present invention can be employed to produce the desired reducedsorbent composition having high attrition resistance and highdesulfurization activity. For example, the acid-treated perlitedescribed in the first embodiment of the present invention can beemployed as the perlite component of the second, third, and fourthembodiments of the present invention. Further, the methods ofincorporating the promoter metal described in the second, third, andfourth embodiments of the present invention can eliminate the metalimpregnating step described in the first embodiment of the presentinvention.

In accordance with another embodiment of the present invention, asorbent composition prepared in accordance with one, or a combination,of the above-described procedures can be employed in a desulfurizationunit to remove sulfur from a sulfur-containing fluid.

Referring to FIG. 1, a desulfurization unit 10 is illustrated asgenerally comprising a fluidized bed reactor 12, a fluidized bedregenerator 14, and a fluidized bed reducer 16. Solid sorbentparticulates are circulated in desulfurization unit 10 to provide forsubstantially continuous sulfur removal from a sulfur-containinghydrocarbon, such as cracked-gasoline or diesel fuel. The sorbentparticulates employed in desulfurization unit 10 are preferably sorbentparticulates made by the sorbent preparation process described above inthe first embodiment of the present invention.

In fluidized bed reactor 12, a hydrocarbon-containing fluid stream ispassed upwardly through a bed of the reduced sorbent particulates. Thereduced sorbent particulates contacted with the hydrocarbon-containingstream in reactor 12 preferably initially (i.e., immediately prior tocontacting with the hydrocarbon-containing fluid stream) compriseperlite, zinc oxide, and the reduced-valence promoter metal component.Though not wishing to be bound by theory, it is believed that thereduced-valence promoter metal component of the reduced sorbentparticulates facilitates the removal of sulfur from thehydrocarbon-containing stream, while the zinc oxide operates as a sulfurstorage mechanism via its conversion to zinc sulfide. Thereduced-valence promoter metal component has a valence which is lessthan the valence of the promoter metal component in its common oxidizedstate. More specifically, the reduced sorbent particulates employed inreactor 12 should include a promoter metal component having a valencewhich is less than the valence of the promoter metal component of theregenerated (i.e., oxidized) sorbent particulates exiting regenerator14.

The hydrocarbon-containing fluid stream contacted with the reducedsorbent particulates in reactor 12 preferably comprises asulfur-containing hydrocarbon and hydrogen. The molar ratio of thehydrogen to the sulfur-containing hydrocarbon charged to reactor 12 ispreferably in the range of from about 0.1:1 to about 3:1, morepreferably in the range of from about 0.2:1 to about 1:1, and mostpreferably in the range of from 0.4:1 to 0.8:1. Preferably, thesulfur-containing hydrocarbon is a fluid which is normally in a liquidstate at standard temperature and pressure, but which exists in agaseous state when combined with hydrogen, as described above, andexposed to the desulfurization conditions in reactor 12. Thesulfur-containing hydrocarbon preferably can be used as a fuel or aprecursor to fuel. Examples of suitable sulfur-containing hydrocarbonsinclude cracked-gasoline, diesel fuels, jet fuels, straight-run naphtha,straight-run distillates, coker gas oil, coker naphtha, alkylates, andstraight-run gas oil. Most preferably, the sulfur-containing hydrocarboncomprises a hydrocarbon fluid selected from the group consisting ofgasoline, cracked-gasoline, diesel fuel, and mixtures thereof.

As used herein, the term “gasoline” denotes a mixture of hydrocarbonsboiling in a range of from about 100° F. to about 400° F., or anyfraction thereof. Examples of suitable gasolines include, but are notlimited to, hydrocarbon streams in refineries such as naphtha,straight-run naphtha, coker naphtha, catalytic gasoline, visbreakernaphtha, alkylates, isomerate, reformate, and the like, and mixturesthereof.

As used herein, the term “cracked-gasoline” denotes a mixture ofhydrocarbons boiling in a range of from about 100° F. to about 400° F.,or any fraction thereof, that are products of either thermal orcatalytic processes that crack larger hydrocarbon molecules into smallermolecules. Examples of suitable thermal processes include, but are notlimited to, coking, thermal cracking, visbreaking, and the like, andcombinations thereof. Examples of suitable catalytic cracking processesinclude, but are not limited to, fluid catalytic cracking, heavy oilcracking, and the like, and combinations thereof. Thus, examples ofsuitable cracked-gasolines include, but are not limited to, cokergasoline, thermally cracked gasoline, visbreaker gasoline, fluidcatalytically cracked gasoline, heavy oil cracked-gasoline and the like,and combinations thereof. In some instances, the cracked-gasoline may befractionated and/or hydrotreated prior to desulfurization when used asthe sulfur-containing fluid in the process in the present invention.

As used herein, the term “diesel fuel” denotes a mixture of hydrocarbonsboiling in a range of from about 300° F. to about 750° F., or anyfraction thereof. Examples of suitable diesel fuels include, but are notlimited to, light cycle oil, kerosene, jet fuel, straight-run diesel,hydrotreated diesel, and the like, and combinations thereof.

The sulfur-containing hydrocarbon described herein as suitable feed inthe inventive desulfurization process comprises a quantity of olefins,aromatics, and sulfur, as well as paraffins and naphthenes. The amountof olefins in gaseous cracked-gasoline is generally in a range of fromabout 10 to about 35 weight percent olefins based on the total weight ofthe gaseous cracked-gasoline. For diesel fuel there is essentially noolefin content. The amount of aromatics in gaseous cracked-gasoline isgenerally in a range of from about 20 to about 40 weight percentaromatics based on the total weight of the gaseous cracked-gasoline. Theamount of aromatics in gaseous diesel fuel is generally in a range offrom about 10 to about 90 weight percent aromatics based on the totalweight of the gaseous diesel fuel. The amount of atomic sulfur in thesulfur-containing hydrocarbon fluid, preferably cracked-gasoline ordiesel fuel, suitable for use in the inventive desulfurization processis generally greater than about 50 parts per million by weight (ppmw) ofthe sulfur-containing hydrocarbon fluid, more preferably in a range offrom about 100 ppmw atomic sulfur to about 10,000 ppmw atomic sulfur,and most preferably from 150 ppmw atomic sulfur to 500 ppmw atomicsulfur. It is preferred for at least about 50 weight percent of theatomic sulfur present in the sulfur-containing hydrocarbon fluidemployed in the present invention to be in the form of organosulfurcompounds. More preferably, at least about 75 weight percent of theatomic sulfur present in the sulfur-containing hydrocarbon fluid is inthe form of organosulfur compounds, and most preferably at least 90weight percent of the atomic sulfur is in the form of organosulfurcompounds. As used herein, “sulfur” used in conjunction with “ppmwsulfur” or the term “atomic sulfur”, denotes the amount of atomic sulfur(about 32 atomic mass units) in the sulfur-containing hydrocarbon, notthe atomic mass, or weight, of a sulfur compound, such as anorganosulfur compound.

As used herein, the term “sulfur” denotes sulfur in any form normallypresent in a sulfur-containing hydrocarbon such as cracked-gasoline ordiesel fuel. Examples of such sulfur which can be removed from asulfur-containing hydrocarbon fluid through the practice of the presentinvention include, but are not limited to, hydrogen sulfide, carbonylsulfide (COS), carbon disulfide (CS₂), mercaptans (RSH), organicsulfides (R—S—R), organic disulfides (R—S—S—R), thiophene, substitutethiophenes, organic trisulfides, organic tetrasulfides, benzothiophene,alkyl thiophenes, alkyl benzothiophenes, alkyl dibenzothiophenes, andthe like, and combinations thereof, as well as heavier molecular weightsof the same which are normally present in sulfur-containing hydrocarbonsof the types contemplated for use in the desulfurization process of thepresent invention, wherein each R can by an alkyl, cycloalkyl, or arylgroup containing one to 10 carbon atoms.

As used herein, the term “fluid” denotes gas, liquid, vapor, andcombinations thereof.

As used herein, the term “gaseous” denotes the state in which thesulfur-containing hydrocarbon fluid, such as cracked-gasoline or dieselfuel, is primarily in a gas or vapor phase.

In fluidized bed reactor 12, the reduced sorbent particulates arecontacted with the upwardly flowing gaseous hydrocarbon-containing fluidstream under a set of desulfurization conditions sufficient to produce adesulfurized hydrocarbon and sulfur-loaded sorbent particulates. Theflow of the hydrocarbon-containing fluid stream is sufficient tofluidize the bed of sorbent particulates located in reactor 12. Thedesulfurization conditions in reactor 12 include temperature, pressure,weighted hourly space velocity (WHSV), and superficial velocity. Thepreferred ranges for such desulfurization conditions are provided belowin Table 3. TABLE 3 Desulfurization Conditions Range Temp Press. WHSVSuperficial Vel. (° F.) (psig) (hr⁻¹) (ft/s) Preferred 250-1200  25-7501-20 0.25-5   More Preferred 500-1000 100-400 2-12 0.5-2.5 MostPreferred 700-850 150-250 3-8  1.0-1.5

When the reduced sorbent particulates are contacted with thehydrocarbon-containing stream in reactor 12 under desulfurizationconditions, sulfur compounds, particularly organosulfur compounds,present in the hydrocarbon-containing fluid stream are removed from suchfluid stream. At least a portion of the sulfur removed from thehydrocarbon-containing fluid stream is employed to convert at least aportion of the zinc oxide of the reduced solid sorbent particulates intozinc sulfide.

In contrast to many conventional sulfur removal processes (e.g.,hydrodesulfurization), it is preferred that substantially none of thesulfur in the sulfur-containing hydrocarbon fluid is converted to, andremains as, hydrogen sulfide during desulfurization in reactor 12.Rather, it is preferred that the fluid effluent from reactor 12(generally comprising the desulfurized hydrocarbon and hydrogen)comprises less than the amount of hydrogen sulfide, if any, in the fluidfeed charged to reactor 12 (generally comprising the sulfur-containinghydrocarbon and hydrogen). The fluid effluent from reactor 12 preferablycontains less than about 50 weight percent of the amount of sulfur inthe fluid feed charged to reactor 12, more preferably less than about 20weight percent of the amount of sulfur in the fluid feed, and mostpreferably less than five weight percent of the amount of sulfur in thefluid feed. It is preferred for the total sulfur content of the fluideffluent from reactor 12 to be less than about 50 parts per million byweight (ppmw) of the total fluid effluent, more preferably less thanabout 30 ppmw, still more preferably less than about 15 ppmw, and mostpreferably less than 10 ppmw.

After desulfurization in reactor 12, the desulfurized hydrocarbon fluid,preferably desulfurized cracked-gasoline or desulfurized diesel fuel,can thereafter be separated and recovered from the fluid effluent andpreferably liquified. The liquification of such desulfurized hydrocarbonfluid can be accomplished by any method or manner known in the art. Theresulting liquified, desulfirized hydrocarbon preferably comprises lessthan about 50 weight percent of the amount of sulfur in thesulfur-containing hydrocarbon (e.g., cracked-gasoline or diesel fuel)charged to the reaction zone, more preferably less than about 20 weightpercent of the amount of sulfur in the sulfur-containing hydrocarbon,and most preferably less than five weight percent of the amount ofsulfur in the sulfur-containing hydrocarbon. The desulfurizedhydrocarbon preferably comprises less than about 50 ppmw sulfur, morepreferably less than about 30 ppmw sulfur, still more preferably lessthan about 15 ppmw sulfur, and most preferably less than 10 ppmw sulfur.

After desulfurization in reactor 12, at least a portion of thesulfur-loaded sorbent particulates are transported to regenerator 14 viaa first transport assembly 18. In regenerator 14, the sulfur-loadedsolid sorbent particulates are contacted with an oxygen-containingregeneration stream. The oxygen-containing regeneration streampreferably comprises at least one mole percent oxygen with the remainderbeing a gaseous diluent. More preferably, the oxygen-containingregeneration stream comprises in the range of from about one to about 50mole percent oxygen and in the range of from about 50 to about 95 molepercent nitrogen, still more preferable in the range of from about twoto about 20 mole percent oxygen and in the range of from about 70 toabout 90 mole percent nitrogen, and most preferably in the range of fromthree to 10 mole percent oxygen and in the range of from 75 to 85 molepercent nitrogen.

The regeneration conditions in regenerator 14 are sufficient to convertat least a portion of the zinc sulfide of the sulfur-loaded sorbentparticulates into zinc oxide via contacting with the oxygen-containingregeneration stream. The preferred ranges for such regenerationconditions are provided below in Table 4. TABLE 4 RegenerationConditions Range Temp Press. Superficial Vel. (° F.) (psig) (ft/s)Preferred 500-1500 10-250 0.5-10  More Preferred 700-1200 20-150 1.0-5.0Most Preferred 900-1100 30-75  2.0-2.5

When the sulfur-loaded sorbent particulates are contacted with theoxygen-containing regeneration stream under the regeneration conditionsdescribed above, at least a portion of the promoter metal component isoxidized to form the oxidized promoter metal component. Preferably, inregenerator 14 the substitutional solid metal solution (M_(A)Zn_(B))and/or sulfided substitutional solid metal solution (M_(A)Zn_(B)S) ofthe sulfur-loaded sorbent is converted to the substitutional solid metaloxide solution (M_(X)Zn_(Y)O).

The regenerated sorbent particulates exiting regenerator 14 preferablycomprise zinc oxide, the oxidized promoter metal component(M_(X)Zn_(Y)O), perlite, and the promoter metal-zinc aluminate(M_(Z)Zn_((1-Z))Al₂O₄) in the ranges provided below in Table 5. TABLE 5Components of the Regenerated Sorbent Particulates Range ZnOM_(X)Zn_(Y)O Perlite M_(Z)Zn_((1-Z))Al₂O₄ (wt %) (wt %) (wt %) (wt %)Preferred  5-80  5-70  5-50 1-50 More Preferred 20-60 15-60 10-40 5-30Most Preferred 30-50 20-40 20-30 10-20 

After regeneration in regenerator 14, the regenerated (i.e., oxidized)sorbent particulates are transported to reducer 16 via a secondtransport assembly 20. In reducer 16, the regenerated sorbentparticulates are contacted with a hydrogen-containing reducing stream.The hydrogen-containing reducing stream preferably comprises at leastabout 50 mole percent hydrogen with the remainder being crackedhydrocarbon products such as, for example, methane, ethane, and propane.More preferably, the hydrogen-containing reducing stream comprises about70 mole percent hydrogen, and most preferably at least 80 mole percenthydrogen. The reducing conditions in reducer 16 are sufficient to reducethe valence of the oxidized promoter metal component of the regeneratedsorbent particulates. The preferred ranges for such reducing conditionsare provided below in Table 6. TABLE 6 Reducing Conditions Range TempPress. Superficial Vel. (° F.) (psig) (ft/s) Preferred 250-1250  25-7500.1-4.0 More Preferred 600-1000 100-400 0.2-2.0 Most Preferred 750-850150-250 0.3-1.0

When the regenerated sorbent particulates are contacted with thehydrogen-containing reducing stream in reducer 16 under the reducingconditions described above, at least a portion of the oxidized promotermetal component is reduced to form the reduced-valence promoter metalcomponent of the reduced sorbent particulates. Preferably, at least asubstantial portion of the substitutional solid metal oxide solution(M_(X)Zn_(Y)O) is converted to the reduced-valence promoter metalcomponent (M_(A)Zn_(B)).

The reduced sorbent particulates preferably comprise zinc oxide, thereduced-valence promoter metal component (M_(A)Zn_(B)), perlite, and thepromoter metal-zinc aluminate substitutional solid(M_(Z)Zn_((1-Z))Al₂O₄) in the ranges provided below in Table 7. TABLE 7Components of the Reduced Sorbent Particulates Range ZnO M_(A)Zn_(B)Perlite M_(Z)Zn_((1-Z))Al₂O₄ (wt %) (wt %) (wt %) (wt %) Preferred  5-80 5-80 2-50 1-50 More Preferred 20-60 20-60 5-30 5-30 Most Preferred30-50 30-40 10-20  10-20 

After the sorbent particulates have been reduced in reducer 16, they canbe transported back to reactor 12 via a third transport assembly 22 forrecontacting with the hydrocarbon-containing fluid stream in reactor 12.

Referring again to FIG. 1, first transport assembly 18 generallycomprises a reactor pneumatic lift 24, a reactor receiver 26, and areactor lockhopper 28 fluidly disposed between reactor 12 andregenerator 14. During operation of desulfurization unit 10 thesulfur-loaded sorbent particulates are continuously withdrawn fromreactor 12 and lifted by reactor pneumatic lift 24 from reactor 12 toreactor receiver 18. Reactor receiver 18 is fluidly coupled to reactor12 via a reactor return line 30. The lift gas used to transport thesulfur-loaded sorbent particulates from reactor 12 to reactor receiver26 is separated from the sulfur-loaded sorbent particulates in reactorreceiver 26 and returned to reactor 12 via reactor return line 30.Reactor lockhopper 26 is operable to transition the sulfur-loadedsorbent particulates from the high pressure hydrocarbon environment ofreactor 12 and reactor receiver 26 to the low pressure oxygenenvironment of regenerator 14. To accomplish this transition, reactorlockhopper 28 periodically receives batches of the sulfur-loaded sorbentparticulates from reactor receiver 26, isolates the sulfur-loadedsorbent particulates from reactor receiver 26 and regenerator 14, andchanges the pressure and composition of the environment surrounding thesulfur-loaded sorbent particulates from a high pressure hydrocarbonenvironment to a low pressure inert (e.g., nitrogen) environment. Afterthe environment of the sulfur-loaded sorbent particulates has beentransitioned, as described above, the sulfur-loaded sorbent particulatesare batch-wise transported from reactor lockhopper 28 to regenerator 14.Because the sulfur-loaded solid particulates are continuously withdrawnfrom reactor 12 but processed in a batch mode in reactor lockhopper 28,reactor receiver 26 functions as a surge vessel wherein thesulfur-loaded sorbent particulates continuously withdrawn from reactor12 can be accumulated between transfers of the sulfur-loaded sorbentparticulates from reactor receiver 26 to reactor lockhopper 28. Thus,reactor receiver 26 and reactor lockhopper 28 cooperate to transitionthe flow of the sulfur-loaded sorbent particulates between reactor 12and regenerator 14 from a continuous mode to a batch mode.

Second transport assembly 20 generally comprises a regenerator pneumaticlift 32, a regenerator receiver 34, and a regenerator lockhopper 36fluidly disposed between regenerator 14 and reducer 16. During operationof desulfurization unit 10 the regenerated sorbent particulates arecontinuously withdrawn from regenerator 14 and lifted by regeneratorpneumatic lift 32 from regenerator 14 to regenerator receiver 34.Regenerator receiver 34 is fluidly coupled to regenerator 14 via aregenerator return line 38. The lift gas used to transport theregenerated sorbent particulates from regenerator 14 to regeneratorreceiver 34 is separated from the regenerated sorbent particulates inregenerator receiver 34 and returned to regenerator 14 via regeneratorreturn line 38. Regenerator lockhopper 36 is operable to transition theregenerated sorbent particulates from the low pressure oxygenenvironment of regenerator 14 and regenerator receiver 34 to the highpressure hydrogen environment of reducer 16. To accomplish thistransition, regenerator lockhopper 36 periodically receives batches ofthe regenerated sorbent particulates from regenerator receiver 34,isolates the regenerated sorbent particulates from regenerator receiver34 and reducer 16, and changes the pressure and composition of theenvironment surrounding the regenerated sorbent particulates from a lowpressure oxygen environment to a high pressure hydrogen environment.After the environment of the regenerated sorbent particulates has beentransitioned, as described above, the regenerated sorbent particulatesare batch-wise transported from regenerator lockhopper 36 to reducer 16.Because the regenerated sorbent particulates are continuously withdrawnfrom regenerator 14 but processed in a batch mode in regeneratorlockhopper 36, regenerator receiver 34 functions as a surge vesselwherein the sorbent particulates continuously withdrawn from regenerator14 can be accumulated between transfers of the regenerated sorbentparticulates from regenerator receiver 34 to regenerator lockhopper 36.Thus, regenerator receiver 34 and regenerator lockhopper 36 cooperate totransition the flow of the regenerated sorbent particulates betweenregenerator 14 and reducer 16 from a continuous mode to a batch mode.

The following examples are presented to further illustrate thisinvention and are not to be construed as unduly limiting the scope ofthis invention.

EXAMPLE I

This example describes the procedure used to prepare six sorbentcompositions (i.e., Sorbents A-F). Sorbents A, C, and E employeduntreated perlite, while Sorbents B, D, and F employed acid-treatedperlite.

Sorbent A was prepared by mixing 974.0 grams of distilled water and166.7 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 452.0 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 171.3 gram quantityof expanded perlite (Harborlite™ 205, available from HarborliteCorporation, Antonito, Colo.) were combined to create a dry mix. The wetmix and dry mix were then combined and mixed to form a sorbent baseslurry.

The sorbent base slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent base slurry was charged tothe spray drier wherein it was contacted in a particulating chamber withair flowing through the chamber. The resulting spray-dried sorbent baseparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulates were then calcined by ramping the oven temperature at5° C./min to 635° C. and holding at 635° C. for 1 hour.

A 150.0 gram quantity of the calcined sorbent base particulates werethen impregnated with a solution containing 149.3 grams of nickelnitrate hexahydrate and 24.3 grams of distilled water using incipientwetness techniques. The impregnated sorbent was then put in an oven anddried by ramping the oven temperature at 3° C./min to 150° C. andholding at 150° C. for 1 hour. The dried sorbent was then calcined byramping the oven temperature at 5° C./min to 635° C. and holding at 635°C. for 1 hour. The resulting nickel-promoted sorbent, formed of 16%nickel, 17.7% alumina, 48.1% zinc oxide, and 18.2% untreated perlite byweight, was designated Sorbent A.

Sorbent B was prepared by mixing 1274.0 grams of distilled water and166.7 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 452.0 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 171.3 gram quantityof acid-treated expanded perlite (Harborlite™ 205, available fromHarborlite Corporation, Antonito, Colo.) were combined to create a drymix. The acid-treated expanded perlite had been pretreated by soaking indistilled water for 1 hour, followed by rinsing four times with oneliter of distilled water, and finally rinsing one time with one liter of5% nitric acid. The wet mix and dry mix were then combined and mixed toform a sorbent base slurry.

The sorbent base slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent base slurry was charged tothe spray drier wherein it was contacted in a particulating chamber withair flowing through the chamber. The resulting spray-dried sorbent baseparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulates were then calcined by ramping the oven temperature at5° C./min to 635° C. and holding at 635° C. for 1 hour.

A 106.8 gram quantity of the calcined sorbent base particulates werethen impregnated with a solution containing 106.3 grams of nickelnitrate hexahydrate and 10.0 grams of distilled water using incipientwetness techniques. The impregnated sorbent was then put in an oven anddried by ramping the oven temperature at 3° C./min to 150° C. andholding at 150° C. for 1 hour. The dried sorbent was then calcined byramping the oven temperature at 5° C./min to 635° C. and holding at 635°C. for 1 hour. The resulting nickel-promoted sorbent, formed of 16%nickel, 17.7% alumina, 48.1% zinc oxide, and 18.2% acid-treated perliteby weight, was designated Sorbent B.

Sorbent C was prepared by mixing 483.0 grams of deionized water and72.86 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 274.75 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 87.39 gram quantityof expanded perlite (Harborlite™ 205, available from HarborliteCorporation, Antonito, Colo.) were combined to create a dry mix. The wetmix and dry mix were then combined and mixed to form a sorbent baseslurry.

The sorbent base slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent base slurry was charged tothe spray drier wherein it was contacted in a particulating chamber withair flowing through the chamber. The resulting spray-dried sorbent baseparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulates were then calcined by ramping the oven temperature at5° C./min to 635° C. and holding at 635° C. for 1 hour.

A 63.0 gram quantity of the calcined sorbent base particulates were thenimpregnated with a solution containing 62.7 grams of nickel nitratehexahydrate and 5.9 grams of distilled water using incipient wetnesstechniques. The impregnated sorbent was then put in an oven and dried byramping the oven temperature at 3° C./min to 150° C. and holding at 150°C. for 1 hour. The dried sorbent was then calcined by ramping the oventemperature at 5° C./min to 635° C. and holding at 635° C. for 1 hour.The resulting nickel-promoted sorbent, formed of 16% nickel, 14.1%alumina, 53.0% zinc oxide, and 16.9% untreated perlite by weight, wasdesignated Sorbent C.

Sorbent D was prepared by mixing 533.0 grams of deionized water and72.86 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 274.75 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 87.39 gram quantityof acid-treated expanded perlite (Harborlite™ 205, available fromHarborlite Corporation, Antonito, Colo.) were combined to create a drymix. The acid-treated expanded perlite had been pretreated by soaking indistilled water for 1 hour, followed by rinsing four times with oneliter of distilled water, and finally rinsing one time with one liter of5% nitric acid. The wet mix and dry mix were then combined and mixed toform a sorbent base slurry.

The sorbent base slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent base slurry was charged tothe spray drier wherein it was contacted in a particulating chamber withair flowing through the chamber. The resulting spray-dried sorbent baseparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulates were then calcined by ramping the oven temperature at5° C./min to 635° C. and holding at 635° C. for 1 hour.

A 100.5 gram quantity of the calcined sorbent base particulates werethen impregnated with a solution containing 100.5 grams of nickelnitrate hexahydrate and 9.5 grams of distilled water using incipientwetness techniques. The impregnated sorbent was then put in an oven anddried by ramping the oven temperature at 3° C./min to 150° C. andholding at 150° C. for 1 hour. The dried sorbent was then calcined byramping the oven temperature at 5° C./min to 635° C. and holding at 635°C. for 1 hour. The resulting nickel-promoted sorbent, formed of 16%nickel, 14.1% alumina, 53.0% zinc oxide, and 16.9% acid-treated perliteby weight, was designated Sorbent D.

Sorbent E was prepared by mixing 1271.0 grams of distilled water and146.0 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 575.0 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 186.9 gram quantityof expanded perlite (Harborlite™ 205, available from HarborliteCorporation, Antonito, Colo.) were combined to create a dry mix. Theperlite had been soaked in sodium hydroxide overnight. The wet mix anddry mix were then combined and mixed to form a sorbent base slurry.

The sorbent base slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent base slurry was charged tothe spray drier wherein it was contacted in a particulating chamber withair flowing through the chamber. The resulting spray-dried sorbent baseparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulates were then calcined by ramping the oven temperature at5° C./min to 635° C. and holding at 635° C. for 1 hour.

A 130.0 gram quantity of the calcined sorbent base particulates werethen impregnated with a solution containing 127.3 grams of nickelnitrate hexahydrate and 12.0 grams of distilled water using incipientwetness techniques. The impregnated sorbent was then put in an oven anddried by ramping the oven temperature at 3° C./min to 150° C. andholding at 150° C. for 1 hour. The dried sorbent was then calcined byramping the oven temperature at 5° C./min to 635° C. and holding at 635°C. for 1 hour. The resulting nickel-promoted sorbent, formed of 16.5%nickel, 13.4% alumina, 52.9% zinc oxide, and 17.2% untreated perlite byweight, was designated Sorbent E.

Sorbent F was prepared by mixing 533.0 grams of deionized water and72.86 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 269.13 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 93.0 gram quantityof acid-treated expanded perlite (Harborlite™ 205, available fromHarborlite Corporation, Antonito, Colo.) were combined to create a drymix. The acid-treated expanded perlite had been pretreated by soaking indistilled water for 1 hour, followed by rinsing four times with oneliter of distilled water, and finally rinsing one time with one liter of5% nitric acid. The wet mix and dry mix were then combined and mixed toform a sorbent base slurry.

The sorbent base slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent base slurry was charged tothe spray drier wherein it was contacted in a particulating chamber withair flowing through the chamber. The resulting spray-dried sorbent baseparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentbase particulates were then calcined by ramping the oven temperature at5° C./min to 635° C. and holding at 635° C. for 1 hour.

A 105.0 gram quantity of the calcined sorbent base particulates werethen impregnated with a solution containing 108.4 grams of nickelnitrate hexahydrate and 10.3 grams of distilled water using incipientwetness techniques. The impregnated sorbent was then put in an oven anddried by ramping the oven temperature at 3° C./min to 150° C. andholding at 150° C. for 1 hour. The dried sorbent was then calcined byramping the oven temperature at 5° C./min to 635° C. and holding at 635°C. for 1 hour. The resulting nickel-promoted sorbent, formed of 16%nickel, 14.0% alumina, 52.0% zinc oxide, and 18.0% acid-treated perliteby weight, was designated Sorbent F.

EXAMPLE 2

In this example, the attrition resistance of Sorbents A-F were tested. A“Fresh” Jet Cup Attrition Index was determined for the freshly preparedSorbents A-F and an Operational Jet Cup Attrition Index was determinedfor Sorbents E and F. Determination of the Jet Cup Attrition Index isdescribed earlier in this application.

The Operational Jet Cup Attrition Index of the sorbent was the Jet CupAttrition Index of the sorbent, measured after a certain repeatedreduction/oxidation (redox) procedure, described in detail below. Therepeated redox procedure was designed to simulate the conditions whichthe sorbent would be exposed to in an actual desulfurization. FIG. 2shows the redox test system 100 used to “age” Sorbents E and F so thatan Operational Jet Cup Attrition Index could be measured. Redox testsystem 100 included a hydrogen source 102, an air source 104, a nitrogensource 106, and a reactor tube 108. Three mass flow controllers 110,112, 114 controlled the flow rate of hydrogen, air, and nitrogen,respectively, through reactor tube 108. The hydrogen and air passedthrough a manual three-way valve 116, which prevented both hydrogen andair from flowing to reactor tube 108 at the same time. Reactor tube 108was a 26-inch quartz reactor tube containing a three-inch upper sectionwith a 0.5-inch outer diameter (O.D.), a 20-inch reactor section(one-inch O.D.) with a glass frit 117 centered in the reactor section,and a three-inch lower section 0.5-inch O.D.). Reactor tube 108 waspositioned in a 15-inch long clam shell furnace 118. A thermocouple 120was disposed at the upper end of reactor tube 108 and extended down intoreactor tube 108, three inches above the glass frit 117. Thermocouple120 was connected to a temperature readout and was not temperaturecontrolling. Two temperature controlling thermocouples 122, 124 wereconnected through the side of two-zone clam shell furnace 118. A sideport 126 at the top of reactor tube 108 was fluidly coupled to a ventline 128. An inlet port 130 of reactor tube 108 is fluidly coupled tohydrogen, air, and nitrogen sources 102, 104, 106 via a supply line 132.

To perform the repeated redox procedure in redox test system 100, thesorbent particulates were first screened to remove particles smallerthan 325 mesh and larger than 100 mesh. A 10 gram quantity of the screensorbent particulates was then loaded on the top of the glass frit 117through the top of reactor tube 108. Nitrogen was then turned on at 200standard cubic centimeters per minute (SCCM) and reactor tube 108 waspurged with nitrogen for 15 minutes. Reactor tube 108 was then heated to800° F. in flowing nitrogen for 15 minutes. The nitrogen flow was thenstopped and the hydrogen flow rate was set to 300 SCCM. The sorbent wasallowed to reduce in flowing hydrogen for one hour. The hydrogen flowwas then stopped, and nitrogen was set to flow at 200 SCCM for 15minutes while reactor tube 108 was heated to 950° F. The nitrogen flowwas then stopped and air was turned on to 100 SCCM and the sorbent wasallowed to oxidize for one hour. The air was then shut off and nitrogenwas allowed to purge reactor tube 108 for 15 minutes at 200 SCCM. Theabove purge, reduction, purge, oxidation, and purge steps were thenrepeated two more times for a total of three redox cycles. After thethree redox cycles, the nitrogen was stopped and the hydrogen flow ratewas set to 300 SCCM and the sorbent was allowed to reduce for one hour.The hydrogen flow was then stopped and nitrogen set to a flow at 200SCCM for 15 minutes. The nitrogen flow was then stopped and reactor tube108 was allowed to cool to ambient temperature. The sorbent, having beensubjected to 3.5 redox cycles, was then removed from reactor tube 108and the Jet Cup Attrition Index of this sorbent was determined in themanner described above. The resulting Jet Cup Attrition Index of the“aged” sorbent subjected to 3.5 redox cycles was its Operational Jet CupAttrition Index.

The “Fresh” Jet Cup Attrition Index (DI) of Sorbents A-F and theOperational Jet Cup Attrition Index of Sorbents E and F, determined inaccordance with the above procedures, are provided below in Table 8.TABLE 8 Ingredients (wt. %) Attrition Resistance Zinc Acid Fresh Oper.%Δ Sorbent Alumina Oxide Perlite Nickel Treated DI DI DI A 17.7 48.118.2 16.0 No 16.9 — — B 17.7 48.1 18.2 16.0 Yes 10.4 — — C 14.1 53.016.9 16.0 No 15.7 — — D 14.1 53.0 16.9 16.0 Yes 10.1 — — E 13.4 52.917.2 16.5 No 10.0 15.8 58.0 F 14.0 52.0 18.0 16.0 Yes 10.8 11.4 5.6

Table 8 shows that the Jet Cup Attrition Index of freshly preparedsorbents employing acid-treated perlite is lower than the Jet CupAttrition Index of freshly prepared sorbents employing untreatedperlite. Such lower Jet Cup Attrition Index for sorbents employingacid-treated perlite indicates enhanced attrition resistance of thesesorbents. Further, Table 8 shows that the difference between the FreshJet Cup Attrition Index and the Operational Jet Cup Attrition Index ofsorbents employing acid-treated perlite is much less than the differencebetween the Fresh Jet Cup Attrition Index and the Operational Jet CupAttrition Index of sorbents employing untreated perlite. Thus, sorbentsemploying acid-treated perlite tend to resist attrition and resistsoftening better than sorbents employing untreated perlite, especiallyafter multiple cycles of reduction and oxidation.

EXAMPLE 3

This example describes the making of a nickel-promoted Sorbent G,wherein nickel is incorporated into the sorbent without requiring anickel impregnation step. Rather than being incorporated byimpregnation, the nickel is pre-reacted with zinc to create anickel-zinc substitutional solid solution which is then mixed with theother components of the sorbent.

A nickel-zinc substitutional solid solution was prepared by mixing866.18 grams of nickel II acetate tetrahydrate and 299.62 grams of zincacetate dihydrate in a beaker with a small amount of deionized water andadded heat. The nickel-zinc mixture was then transferred to a quartzdish and calcined on a belt calciner for 1.5 hours at 635° C. Theresulting calcined nickel-zinc mixture was placed in a ball mill andsubjected to particle size reduction in the ball mill for 5 minutes.

A 1022.0 gram quantity of distilled water and 146.0 grams of aluminumhydroxide powder (Dispal® Alumina Powder, available from CONDEA VistaCompany, Houston, Tex.) were mixed to create a wet mix. In a separatecontainer, a 835.0 gram quantity of the milled nickel-zinc mixture and a150.0 gram quantity of expanded perlite (Harborlite™ 205, available fromHarborlite Corporation, Antonito, Colo.) were combined to create a drymix. The wet mix and dry mix were then combined and mixed to form asorbent slurry. A 55.0 gram quantity of 5% nitric acid was added to thesorbent slurry to bring the pH of the slurry to 6.0.

The sorbent slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent slurry was charged to thespray drier wherein it was contacted in a particulating chamber with airflowing through the chamber. The resulting spray-dried sorbentparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent base particulates werethen placed in an oven and dried by ramping the oven temperature at 3°C./min to 150° C. and holding at 150° C. for 1 hour. The dried sorbentparticulates were then calcined by ramping the oven temperature at 5°C./min to 635° C. and holding at 635° C. for 1 hour. The resultingnickel-promoted sorbent was designated Sorbent G. The Jet Cup AttritionIndex of Sorbent G was 16.7.

EXAMPLE 4

This example describes the making of a nickel-promoted Sorbent H,wherein nickel is incorporated into the sorbent without requiring anickel impregnation step. Rather than being incorporated byimpregnation, the nickel is dissolved in the distilled water used tocreate a spray-dryable slurry of the sorbent components.

Sorbent H was prepared by mixing 608.0 grams of distilled water and695.0 grams of nickel nitrate hexahydrate to form a nickel solution. A146.0 gram quantity of aluminum hydroxide powder (Disperal® AluminaPowder, available from CONDEA Vista Company, Houston, Tex.) was added tothe nickel solution to create a wet mix. In a separate container, a575.0 gram quantity of zinc oxide powder (available from ZincCorporation, Monaca, Pa.) and a 150 gram quantity of expanded perlite(Sil-Kleer™ 27M, available from Silbrico Corporation, Hodgkins, Ill.)were combined to create a dry mix. The wet mix and dry mix were thencombined and mixed to form a sorbent slurry.

The sorbent slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent slurry was charged to thespray drier wherein it was contacted in a particulating chamber with airflowing through the chamber. The resulting spray-dried sorbentparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent particulates were thenplaced in an oven and dried by ramping the oven temperature at 3° C./minto 150° C. and holding at 150° C. for 1 hour. The dried sorbentparticulates were then calcined by ramping the oven temperature at 5°C./min to 635° C. and holding at 635° C. for 1 hour. The resultingnickel-promoted sorbent was designated Sorbent H. The Jet Cup AttritionIndex of Sorbent H was 5.5.

EXAMPLE 5

This example describes the making of a nickel-promoted Sorbent I,wherein nickel is incorporated into the sorbent without requiring anickel impregnation step. Rather than being incorporated byimpregnation, the nickel is incorporated as nickel oxide in the dry mixused to create a slurry of the sorbent components.

Sorbent I was prepared by mixing 1218.0 grams of distilled water and155.3 grams of aluminum hydroxide powder (Dispal® Alumina Powder,available from CONDEA Vista Company, Houston, Tex.) to create a wet mix.In a separate container, a 574.2 gram quantity of zinc oxide powder(available from Zinc Corporation, Monaca, Pa.) and a 150.0 gram quantityof expanded perlite (Sil-Kleer™ 27M, available from SilbricoCorporation, Hodgkins, Ill.) were mixed. A 253.44 gram quantity ofnickel oxide was then combined with the aluminum hydroxide and zincoxide to create a dry mix. The wet mix and dry mix were then combinedand mixed to form a sorbent slurry.

The sorbent slurry was formed into sorbent particulates using acounter-current spray drier (Niro Atomizer Model 68, available from NiroAtomizer, Inc., Columbia, Md.). The sorbent slurry was charged to thespray drier wherein it was contacted in a particulating chamber with airflowing through the chamber. The resulting spray-dried sorbentparticulates were then sieved to remove particles larger than 100 meshand smaller than 635 mesh. The sieved sorbent particulates were thenplaced in an oven and dried by ramping the oven temperature at 3° C./minto 150° C. and holding at 150° C. for 1 hour. The dried sorbentparticulates were then calcined by ramping the oven temperature at 5°C./min to 635° C. and holding at 635° C. for 1 hour. The resultingnickel-promoted sorbent was designated Sorbent I. The Jet Cup AttritionIndex of Sorbent I was 18.7.

Reasonable variations, modifications, and adaptations may be made withinthe scope of this disclosure and the appended claims without departingfrom the scope of this invention.

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 55. An unreduced sorbentcomposition prepared by a method comprising: (a) contacting expanded,crushed perlite with an acid to thereby provide an acid-treated perlite,and (b) combining said acid-treated perlite with a zinc source, analuminum source and a promoter metal to thereby provide said unreducedsorbent.
 56. An unreduced sorbent composition prepared by a method ofclaim comprising: (a) reacting a promoter metal-containing compound witha zinc-containing compound under conditions sufficient to form asubstitutional solid solution comprising a promoter metal and zinc; and(b) combining said substitutional solid solution with a zinc source andaluminum source to thereby provide said unreduced sorbent.
 57. A reducedsorbent composition prepared by a method of claim comprising: (a)admixing a solvent, a promoter metal, and an alumina to thereby form awet mix; (b) admixing zinc oxide and perlite to thereby form a dry mix;(c) admixing said wet mix and said dry mix to thereby form a sorbentslurry; (d) particulating said sorbent slurry to thereby form sorbentparticulates: (e) calcining said sorbent particulates to thereby formcalcined sorbent particulates: and (f) reducing said calcined sorbentparticulates to thereby form said reduced sorbent.
 58. A reduced sorbentcomposition prepared by a method comprising (a) admixing a solvent andalumina to thereby form a wet mix; (b) admixing zinc oxide, an oxide ofa promoter metal, and perlite to thereby form a dry mix; (c) admixingsaid wet mix and said dry mix to thereby form a sorbent slurry; (d)particulating said sorbent slurry to thereby form sorbent particulates;(e) calcining said sorbent particulates to thereby form calcined sorbentparticulates; and (f) reducing said calcined sorbent particulates tothereby form said reduced sorbent.
 59. A method of making a sorbentcomposition, said method comprising the steps of: (a) admixing asolvent, an acid, and perlite so as to form a first mixture; (b)admixing a solvent, an aluminum source, and a clay so as to form asecond mixture; (c) combining said first mixture and said second mixtureso as to form a third mixture; (d) adding zinc oxide to said thirdmixture so as to form a zinc oxide mixture; (e) drying said zinc oxidemixture so as to form a first dried mixture; (f) calcining said firstdried mixture so as to form a first calcined mixture; (g) incorporatinga promoter into or onto said first calcined mixture so as to form apromoted mixture; (h) drying said promoted mixture so as to form asecond dried mixture; and (i) calcining said second dried mixture so asto form a second calcined mixture.
 60. A method according to claim 59,wherein said aluminum source is alumina, and wherein said promoter isselected from the group consisting of nickel, cobalt, iron, manganese,copper, zinc, molybdenum, tungsten, silver, antimony, and vanadium. 61.A method according to claim 60, wherein said promoter is nickel.
 62. Amethod according to claim 59, further comprising the step of: (j)reducing said second calcined mixture with a hydrogen-containingreducing fluid to thereby provide a reduced sorbent.
 63. A methodaccording to claim 59 wherein said zinc oxide mixture from step (d) isparticulated prior to said drying in step (e).
 64. A method according toclaim 59 wherein said calcining in steps (f) and (i) occurs at atemperature in the range of from about 4000 to about 1800° F.
 65. Amethod according to claim 59 wherein during said calcining of step (i),at least a portion of said zinc oxide and at least a portion of saidpromoter combine to form a oxidized promoter metal component comprisinga substitutional solid metal oxide solution characterized by the formulaM_(X)Zn_(Y)O, wherein M is said promoter and X and Y are numericalvalues in the range of from about 0.01 to about 0.99.
 66. A methodaccording to claim 62 wherein said reducing is operable to reduce atleast a portion of said second calcined mixture to a substitutionalsolid metal solution characterized by the formula M_(A)Zn_(B), wherein Mis said promoter and A and B are numerical values in the range of fromabout 0.01 to about 0.99.
 67. A method according to claim 66 whereinsaid aluminum source is alumina, said promoter is selected from thegroup consisting of nickel, cobalt, iron, manganese, copper, zinc,molybdenum, tungsten, silver, antimony, and vanadium, A is in the rangeof from about 0.70 to about 0.97, B is in the range of from about 0.03to about 0.30, X is in the range of from about 0.5 to about 0.9, and Yis in the range of from about 0.1 to about 0.5.
 68. A method accordingto claim 59 wherein step (d) includes chemically combining at least aportion of said zinc oxide and at least a portion of said aluminumsource to form a spinel structure similar to zinc aluminate.
 69. Amethod according to claim 68 wherein during said calcining at least aportion of said promoter and at least a portion said zinc aluminatecombine to form a promoter-zinc aluminate substitutional solid solutioncharacterized by the formula M_(Z)Zn_((1-z))Al₂O₄, wherein M is saidpromoter and Z is a numerical value in the range of from 0.01 to 0.99.70. A method according to claim 69 wherein said second calcined mixturecomprises said zinc oxide in an amount in the range of from about 20 toabout 60 weight percent, said substitutional solid metal solution in therange of from about 20 to about 60 weight percent, said perlite in theamount of from about 10 to about 40 weight percent and saidpromoter-zinc aluminate substitutional solid solution in the range offrom about 5 to about 30 weight percent.
 71. A method according to claim59 wherein said clay is kaolin clay.
 72. A method according to claim 59wherein said clay is present in said zinc oxide mixture in a weightratio of from about 0.1:1 to about 20:1 zinc oxide to clay.
 73. A methodaccording to claim 59 wherein said clay is present in said zinc oxidemixture in a weight ratio of from about 1:1 to about 10:1 zinc oxide toclay.
 74. A method according to claim 59 wherein said acid is nitricacid.
 75. A method of making a sorbent composition, said methodcomprising the steps of: (a) admixing a solvent, an acid, an aluminumsource, perlite, and zinc oxide so as to form a mixture thereof; (b)adding a promoter to said mixture so as to form a promoted mixture; (c)drying said promoted mixture so as to form a dried mixture; and (d)calcining said dried mixture so as to form a calcined mixture.
 76. Amethod according to claim 75, wherein said aluminum source is alumina,and wherein said promoter is selected from the group consisting ofnickel, cobalt, iron, manganese, copper, zinc, molybdenum, tungsten,silver, antimony, and vanadium.
 77. A method according to claim 76,wherein said promoter is nickel.
 78. A method according to claim 75,further comprising the step of: (e) reducing said calcined mixture witha hydrogen-containing reducing fluid to thereby provide a reducedsorbent.
 79. A method according to claim 75 wherein said calcining insteps (d) occurs at a temperature in the range of from about 400° toabout 1800° F.
 80. A method according to claim 75 wherein during saidcalcining of step (d), at least a portion of said zinc oxide and atleast a portion of said promoter combine to form a oxidized promotermetal component comprising a substitutional solid metal oxide solutioncharacterized by the formula M_(X)Zn_(Y)O, wherein M is said promoterand X and Y are numerical values in the range of from about 0.01 toabout 0.99.
 81. A method according to claim 78 wherein said reducing isoperable to reduce at least a portion of said calcined mixture to asubstitutional solid metal solution characterized by the formulaM_(A)Zn_(B), wherein M is said promoter and A and B are numerical valuesin the range of from about 0.01 to about 0.99.
 82. A method according toclaim 81 wherein said aluminum source is alumina, said promoter isselected from the group consisting of nickel, cobalt, iron, manganese,copper, zinc, molybdenum, tungsten, silver, antimony, and vanadium, A isin the range of from about 0.70 to about 0.97, B is in the range of fromabout 0.03 to about 0.30, X is in the range of from about 0.5 to about0.9, and Y is in the range of from about 0.1 to about 0.5.
 83. A methodaccording to claim 75 wherein step (a) includes chemically combining atleast a portion of said zinc oxide and at least a portion of saidaluminum source to form a spinel structure similar to zinc aluminate.84. A method according to claim 83 wherein during said calcining atleast a portion of said promoter and at least a portion said zincaluminate combine to form a promoter-zinc aluminate substitutional solidsolution characterized by the formula M_(Z)Zn_((1-Z))Al₂O₄, wherein M issaid promoter and Z is a numerical value in the range of from 0.01 to0.99.
 85. A method according to claim 84 wherein said calcined mixturecomprises said zinc oxide in an amount in the range of from about 20 toabout 60 weight percent, said substitutional solid metal solution in therange of from about 20 to about 60 weight percent, said perlite in theamount of from about 10 to about 40 weight percent and saidpromoter-zinc aluminate substitutional solid solution in the range offrom about 5 to about 30 weight percent.
 86. A method in accordance withclaim 75 wherein clay is included in said mixture of step (a).
 87. Amethod according to claim 86 wherein said clay is present in said zincoxide mixture in a weight ratio of from about 0.1:1 to about 20:1 zincoxide to clay.
 88. A method according to claim 75 wherein said acid isnitric acid.
 89. A composition produced by the method of claim
 59. 90. Acomposition produced by the method of claim
 62. 91. A compositionproduced by the method of claim
 75. 92. A composition produced by themethod of claim 78.